A multi-channel 3D camera system obtains digital images of an object from multiple view points, which can be used to generate a 3D image of the object. One such 3D camera system is an intra-oral scanner used to generate a 3D digital model of teeth. Using an intra-oral scanner requires a particular positioning to obtain electronic images of the intra-oral structures to accurately generate a corresponding 3D model. Accordingly, there is a need to extend the depth of the field of a 3D camera system to ease the scanning ability in a dental scanner or other types of scanner.